Morphofunctional disparity in the radiation of South American squirrels of the tribe Sciurini

• Grant number: 24/16129-7
• Support Opportunities: Scholarships in Brazil - Master
• Start date: February 01, 2025
• End date: October 31, 2026
• Field of knowledge: Biological Sciences - Zoology - Taxonomy of Recent Groups
• Principal Investigator: Alexandre Reis Percequillo
• Grantee: Marcos Angelo Alves Filho
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 20/11444-0 - Diversity of neotropical rodents (Rodentia: Sciuridae, Cricetidae, Echimyidae): origin, evolution and biogeography, AP.TEM

Abstract

The South American squirrels are extremely diverse, both taxonomically and phylogenetically. These arboreal rodents play crucial roles in ecosystems and are structured across different ecological niches. In 2020, Abreu et al. published a systematic study based on molecular data that challenged the current taxonomic classification of the tribe Sciurini (which includes the vast majority of South American arboreal squirrels) and suggested that the diversity of both genera and species is underestimated. Arboreal squirrels colonized South America around 6 million years ago and quickly diversified, occupying almost all of the continent's tropical forests. This process, which occurred throughout the Pliocene, suggests adaptive radiation of these lineages in South America. However, due to the conservative nature of the traditionally analyzed morphological attributes in species, the adaptive nature of this diversification, as well as other macroevolutionary phenotypic issues, remains undefined. In this context, deviating from the parameters traditionally used in morphological studies, the present master's project aims to access, in a pioneering manner for South American squirrels, internal cranial structures, seeking to understand their morphological variations from an evolutionary perspective. Additionally, I intend to investigate whether the disparity found among different taxa is more related to phylogenetic or environmental aspects. To achieve this, an innovative approach will be used through CTscan techniques and 3D segmentation, which have already shown great potential in mammal evolution and taxonomy studies. The results obtained should contribute not only to a broader morphofunctional understanding of the tribe Sciurini but also to a better understanding of the ecomorphological and adaptive aspects of rodents, benefiting various fields of biodiversity and conservation studies.